Production was quite high in '54 as the Brits were working 24/7 building 350s for India. This is why the Indians took over production as the factory was having trouble filling the order.
But in '54 the factory was building all the bikes. As mentioned above, yours would be more likely an 350 and was possibly an export to India.
The next year or so, after the Indians had the long term contract settled, the factory made a deal with them to partially produce the bikes and started sending them kits rather than fully assembled bikes, then started sending them 1955 tooling s they could start building parts and subassemblies. In 1962, all the tooling had been sent to them and the Indians started producing the complete bike. They didn't start selling civilian models until about '75. The 500s came out in '89